Drug resistant TB warning

The World Health Organization (WHO) has expressed concern over the emergence of virulent drug-resistant strains of tuberculosis (TB).

It is calling for measures to be strengthened and implemented to prevent the global spread of the deadly TB strains.

New research has shown the frightening extent of XDR-TB, a newly identified TB threat which leaves patients (including many people living with HIV) virtually untreatable using currently available anti-TB drugs. The WHO says that XDR-TB poses a grave public health threat, especially in populations with high rates of HIV and where there are few health care resources.

WHO is joining other TB experts at a two-day meeting in South Africa (7-8 September) to consider what the response should be to tackle the TB drug resistance, particularly in Africa.

MDR-TB (Multidrug Resistant TB) is a type of tuberculosis that is resistant to at least the two main first-line TB drugs - isoniazid and rifampicin. XDR-TB, or Extensive Drug Resistant TB (also referred to as Extreme Drug Resistance) is MDR-TB that is also resistant to three or more of the six classes of second-line drugs.

Resistance to anti-TB drugs is primarily due to poorly managed TB care. Problems include incorrect drug prescribing, poor quality drugs or erratic supply of drugs, and also patients not carrying on taking the full course of their drugs.

XDR-TB has now been identified in all regions of the world but particularly in the countries of the former Soviet Union and in Asia. In the United States, 4% of TB cases were XDR-TB, and in Latvia, a country with one of the highest rates of MDR-TB, 19% of MDR-TB cases met the XDR-TB criteria.

Separate data on a recent outbreak of XDR-TB in an HIV-positive population in Kwazulu-Natal in South Africa had 'alarmingly high mortality rates' say the WHO.

In Africa it seems that drug resistance in the region is on the rise; given the underlying HIV epidemic, drug-resistant TB could have an enormous impact on mortality and requires urgent action.

Paul Sommerfeld of TB Alert, said: "XDR TB is very serious - we are potentially getting close to a bacteria that we have no tools, no weapons against. What this means for the people in southern Africa, who are now becoming susceptible to this where it is appearing, is a likely death sentence. For the world as a whole it is potentially extremely worrying that this kind of resistance is appearing. This is something that I am sure the WHO will be taking very seriously."